Prevalence and relative risk of canine dirofilariosis among dogs in Seoul, South Korea.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
B H Chung
Publications and source records attributed to B H Chung.
Refolding and purification of yeast carboxypeptidase Y expressed as inclusion bodies in Escherichia coli.
The genes encoding carboxypeptidase Y (CPY) and CPY propeptide (CPYPR) from Saccharomyces cerevisiae were cloned and expressed in Escherichia coli. Six consecutive histidine residues were fused to the C-terminus of the CPYPR for facilitated purification. High-level expression of CPY and CPYPR-His(6) was achieved but most of the expressed proteins were present in the form of inclusion bodies in the bacterial cytoplasm. The CPY and CPYPR-His(6) produced as inclusion bodies were separated from the cells and solubilized in 6 and 3 M guanidinium chloride, respectively. The denatured CPYPR-His(6) was refolded by dilution 1:30 into the renaturation buffer (50 mM Tris-HCl containing 0.5 M NaCl and 3 mM EDTA, pH 8.0), and the refolded CPYPR-His(6) was further purified to 90% purity by single-step immobilized metal ion affinity chromatography. The denatured CPY was refolded by dilution 1:60 into the renaturation buffer containing CPYPR-His(6) at various concentrations. Increasing the molar ratio of CPYPR-His(6) to CPY resulted in an increase in the CPY refolding yield, indicating that the CPYPR-His(6) plays a chaperone-like role in in vitro folding of CPY. The refolded CPY was purified to 92% purity by single-step p-aminobenzylsuccinic acid affinity chromatography. When refolding was carried out in the presence of 10 molar eq CPYPR-His(6), the specific activity, N-(2-furanacryloyl)-l-phenylalanyl-l-phenylalanine hydrolysis activity per milligram of protein, of purified recombinant CPY was found to be about 63% of that of native S. cerevisiae CPY.
Carboxypeptidases↗
Structure-activity relationship studies of isoquinolinone type anticancer agent.
Substituted isoquinolin-1-ones (1) were synthesized to test their in vitro anticancer activity. 3-Biphenyl-N-methylisoquinolin-1-one (7) showed the most potent anticancer activity against five different human cancer cell lines.
Antineoplastic Agents↗
Current status of the anticoagulant hirudin: its biotechnological production and clinical practice.
Hirudin is a potent thrombin inhibitor originally derived from the medicinal leech, Hirudo medicinalis. Owing to its high affinity and specificity for thrombin, hirudin has been intensively investigated for research and therapeutic purposes. The investigation of hirudin has contributed greatly to the understanding of the mode of action of thrombin and the clotting system. Hirudin and several hirudin analogues have also been demonstrated to have several advantages as a highly specific anticoagulant over the most widely used drug, heparin. Due to the great demand for hirudin in physicochemical and clinical studies, various recombinant systems have been developed, using bacteria, yeasts, and higher eukaryotes, to obtain the biologically active hirudin in significant quantities. After 10 years of clinical applications, two recombinant hirudins and a hirudin analogue have gained marketing approval from the United States Food and Drug Administration, for several applications. Clinical trials are currently ongoing for other treatments for thrombotic disease. As a consequence, it is conceivable that hirudin may expand its therapeutic utility over heparin in the near future.
Amino Acid Sequence↗
Effects of docosahexaenoic acid and eicosapentaenoic acid on androgen-mediated cell growth and gene expression in LNCaP prostate cancer cells.
There is some epidemiological support for a protective influence of omega-3 fatty acids against prostate cancer. We wanted to explore whether omega-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) can affect androgen receptor function in prostate cancer cells. Our study showed that both DHA and EPA inhibit androgen-stimulated cell growth. Androgenic induction of prostate-specific antigen (PSA) protein was repressed by DHA and EPA in a dose-dependent manner. The mRNA levels of five androgen up-regulated genes, PSA, ornithine decarboxylase, NKX 3.1, immunophilin fkbp 51 and Drg-1, were decreased with DHA treatment in the presence of androgens. Transfection experiments using a DNA vector containing androgen-responsive elements demonstrated that both DHA and EPA could interfere with transactivation activities of the androgen receptor (AR). However, western blot analysis of AR protein showed that DHA and EPA treatments did not change AR expression levels. Interestingly, the proto-oncoprotein c-jun was increased by DHA treatment. A transient transfection found that forced expression of c-jun inhibited AR transactivation activity. Thus, this study found that the inhibitory effects of omega-3 polyunsaturated fatty acids on AR-mediated actions are due, at least in part, to an increase in c-jun protein.
Androgen Receptor Antagonists↗
Cationic domain 141-150 of apoE covalently linked to a class A amphipathic helix enhances atherogenic lipoprotein metabolism in vitro and in vivo.
We previously showed 1 that a peptide, Ac-hE18A-NH(2), in which the arginine-rich heparin-binding domain of apolipoprotein E (apoE) [residues 141;-150] (LRKLRKRLLR), covalently linked to 18A (DWLKAFYDKVAEKLKEAF; a class A amphipathic helix with high lipid affinity), enhanced LDL uptake and clearance. Because VLDL and remnants contain more cholesterol per particle than LDL, enhanced hepatic clearance of VLDL could lead to an effective lowering of plasma cholesterol. Therefore, in the present article we compared the ability of this peptide to mediate/facilitate the uptake and degradation of LDL and VLDL in HepG2 cells. The peptide Ac-hE18A-NH(2), but not Ac-18A-NH(2), enhanced the uptake of LDL by HepG2 cells 5-fold and its degradation 2-fold. The association of the peptides with VLDL resulted in the displacement of native apoE; however, only Ac-hE18A-NH(2) but not Ac-18A-NH(2) caused markedly enhanced uptake (6-fold) and degradation (3-fold) of VLDL. Ac-hE18A-NH(2) also enhanced the uptake (15-fold) and degradation (2-fold) of trypsinized VLDL Sf 100;-400 (containing no immuno-detectable apoE), indicating that the peptide restored the cellular interaction of VLDL in the absence of its essential native ligand (apoE). Pretreatment of HepG2s with heparinase and heparitinase abrogated all peptide-mediated enhanced cellular activity, implicating a role for cell-surface heparan sulfate proteoglycans (HSPG). Intravenous administration of Ac-hE18A-NH(2) into apoE gene knockout mice reduced plasma cholesterol by 88% at 6 h and 30% at 24 h after injection. We conclude that this dual-domain peptide associates with LDL and VLDL and results in rapid hepatic uptake via a HSPG-facilitated pathway.
Amino Acid Sequence↗
Successfully treated renal fungal ball with continuous irrigation of fluconazole.
Explore the source record for details and available documents.
Antifungal Agents↗
The receptor binding domain of apolipoprotein E, linked to a model class A amphipathic helix, enhances internalization and degradation of LDL by fibroblasts.
Human apolipoprotein E (apo E) consists of two distinct domains, the lipid-associating domain (residues 192-299) and the globular domain (residues 1-191) which contains the LDL receptor (LDLR) binding site (residues 129-169). To test the hypothesis that an arginine-rich apo E receptor binding domain (residues 141-150) is sufficient to enhance low-density lipoprotein (LDL) uptake and clearance when covalently linked to a class A amphipathic helix, a peptide in which the receptor binding domain of human apo E, LRKLRKRLLR (hApoE[141-150]), is linked to 18A, a well-characterized high-affinity lipid-associating peptide (DWLKAFYDKVAEKLKEAF), we synthesized the peptide hApoE[141-150]-18A (hE18A) and its end-protected analogue, Ac-hE18A-NH(2). The importance of positively charged residues and the role of the hydrophobic residues in the receptor binding domain were also studied using four analogues. Ac-LRRLRRRLLR-18A-NH(2) [Ac-hE(R)18A-NH(2)] and Ac-LRKMRKRLMR-18A-NH(2) (Ac-mE18A-NH(2)) contained an extended hydrophobic face, including the receptor binding region. Control peptides, Ac-LRLLRKLKRR-18A-NH(2) [Ac-hE(Sc)18A-NH(2)], had the amino acid residues of the apo E receptor binding domain scrambled to disrupt the extended hydrophobic face, and Ac-RRRRRRRRRR-18A-NH(2) (Ac-R(10)18A-NH(2)) had only positively charged Arg residues as the receptor binding domain. The effect of the dual-domain peptides on the uptake and degradation of human LDL by fibroblasts was determined in murine embryonic fibroblasts (MEF1). LDL internalization was enhanced 3-, 5-, and 7-fold by Ac-mE18A-NH(2), Ac-hE18A-NH(2), and Ac-hE(R)18A-NH(2), respectively, whereas the control peptides had no significant biological activity. All three active peptides increased the level of degradation of LDL by 100%. The LDL binding and internalization to MEF1 cells in the presence of these peptides was not saturable over the LDL concentration range that was studied (1-10 microgram/mL). Furthermore, a similar enhancement of LDL internalization was observed independent of the presence of the LDL receptor-related protein (LRP), LDLR, or both. Pretreatment of cells with heparinase and heparitinase abolished more than 80% of the enhanced peptide-mediated LDL uptake and degradation by cells. We conclude that the dual-domain peptides enhanced LDL uptake and degradation by fibroblasts via a heparan sulfate proteoglycan (HSPG)-mediated pathway.
Amino Acid Sequence↗
Refolding and purification of Zymomonas mobilis levansucrase produced as inclusion bodies in fed-batch culture of recombinant Escherichia coli.
Zymomonas mobilis levansucrase was overproduced by the fed-batch culture of recombinant Escherichia coli harboring a novel expression system that is constitutively expressed by the promoter from the Rahnella aquatilis levansucrase gene. Most of the levansucrase was produced as inclusion bodies in the bacterial cytoplasm, accounting for approximately 20% of the total cellular protein. Refolding after complete denaturation by high concentrations of urea or guanidine hydrochloride was not successful, resulting in large amounts of insoluble aggregates. During the development of the refolding method, it was found that direct solubilization of the inclusion bodies with Triton X-100 reactivated the enzyme, with a considerable refolding efficiency. About 65% of inclusion body levansucrase was refolded into active levansucrase in the renaturation buffer containing 4% (v/v) Triton X-100. The in vitro refolded enzyme was purified to 95% purity by single-step DEAE-Sepharose ion exchange chromatography. Triton X-100 was removed by this ion exchange chromatography.
Amino Acids↗
Improvement of intact human lipocortin-I production in Saccharomyces cerevisiae by inhibiting proteolysis.
Human lipocortin-I (hLC1), when was expressed as a secretory product in Saccharomyces cerevisiae, was cleaved to a significant extent by endoproteolytic processing, resulting in the accumulation of des1-26-hLC1 in the culture supernatant. This proteolytic cleavage was inhibited significantly by the addition of high concentrations of l-arginine and l-lysine, with a resultant marked improvement in the yield of intact hLC1. When the hLC1 was expressed in S. cerevisiae mutants deficient in one or two of the following endoproteases, Kex2p, Mkc7p and Yps1p (Yap3p), the mutants exhibited no reduction in the extent of hLC1 proteolysis, indicating that these endoproteases are not involved in the proteolytic cleavage of hLC1.
Journal Article↗
Comparison of single and multiple sessions of percutaneous sclerotherapy for simple renal cyst.
OBJECTIVE: To compare the results of single and repeated percutaneous sclerotherapy in patients with simple renal cysts. PATIENTS AND METHODS: Eighty-two patients with simple renal cysts underwent needle aspiration andsclerotherapy under ultrasonographic guidance. Forty-two patients (group 1) underwent one session of sclerotherapy with 99% ethanol immediately after aspiration and 40 patients (group 2) underwent sclerotherapy at least twice. The patients were followed up using ultrasonography at 3-month intervals. The complete disappearance or a reduction of more than half in the diameter of the renal cyst was considered a successful treatment. RESULTS: The mean diameter of the renal cysts was not significantly different in group 1 (6.12 cm) and 2 (6.75 cm). There was complete or partial regression in eight (19%) and 16 (38%) in group 1, and in 29 (73%) and nine (23%) in group 2, respectively. The overall success rate was significantly better in group 2 (95%) than in group 1 (57%; P < 0.001). CONCLUSIONS: These results suggest that multiple sclerotherapy is better than a single injection of sclerosant for reducing the recurrence of simple renal cysts.
Adult↗
Protein kinase C independent activation of inducible nitric oxide synthase by tumor necrosis factor-alpha in TM4 Sertoli cells.
To investigate the nitric oxide (NO) production and its signalling mechanism in TM4 Sertoli cells, the cells were treated with recombinant tumor necrosis factor-alpha (rTNF-alpha), recombinant interleukin-1 alpha (rIL-1alpha), or lipopolysaccharide (LPS), either alone or in combination with recombinant interferon-gamma (rIFN-gamma), and NO production was measured by using the Griess method. TM4 Sertoli cells produced a small amount of NO upon treatment with rIFN-gamma. The effect of rIFN-gamma was drastically increased by cotreatment with rTNF-alpha in a dose-dependent manner. However, combination of rIL-1alpha or LPS with rIFN-gamma did not synergize to activate cells. RIFN-gamma in combination with rTNF-alpha showed marked increase of the expression of iNOS protein. Protein kinase C inhibitors did not inhibit the production of NO induced by rIFN-gamma plus rTNF-alpha. These results suggest that the role of TNF-alpha is to provide TM4 Sertoli cells with the active cofactor for NO production and TNF-alpha-induced signaling for induction of NO synthesis is not dependent on protein kinase C activation.
Animals↗
Inflammatory pseudotumor of urinary bladder.
A previously healthy 44-year-old male was admitted with the chief complaint of intermittent gross hematuria. On initial ultrasonographic and CT examination, a grossly protruding intravesical tumor was noted and, under the impression of a malignant bladder tumor, transurethral resection was performed. The histological findings were spindle cells with elongated cytoplasm with rare mitotic figures distributed in myxoid stroma, consistent with diagnosis of inflammatory pseudotumor of the bladder. The benign nature of this tumor warrants conservative surgical management, usually consisting of transurethral resection or partial cystectomy. No reports of metastasis have been reported following complete excision. Therefore, any suspicion and recognition of this entity is imperative to avoid performing an irreversible radical procedure.
Adult↗
Lipolytic remnants of human VLDL produced in vitro. Effect of HDL levels in the lipolysis mixtures on the apoCs to apoE ratio and metabolic properties of VLDL core remnants.
To determine the role of high-density lipoprotein (HDL) as an acceptor of lipolytic surface remnants of very low density lipoprotein (VLDL) in the metabolism of VLDL core remnants, we examined the effect of HDL levels in the VLDL lipolysis mixture on 1) the morphology and the apoCs to E ratio in VLDL core remnants and 2) the metabolic properties of VLDL core remnants in human hepatoma cell line HepG2 and human hepatocytes in the primary culture. Normolipidemic VLDL was lipolyzed in vitro by purified bovine milk lipoprotein lipase (LpL) in a lipolysis mixture containing a physiologic level of VLDL and albumin (30 mg VLDL-cholesterol (CH)/dl and 6% albumin) in the absence and presence of either a low HDL level (VLDL-CH:HDL-CH = 3:1) or a high HDL level (VLDL-CH:HDL-CH = 1:4). Lipolysis of VLDL in either the absence or presence of HDL resulted in the hydrolysis of >85% of VLDL-triglycerides (TG) and the conversion of VLDL into smaller and denser particles. In the absence of HDL, heterogeneous spherical particles with numerous surface vesicular materials were produced. In the presence of low or high HDL, spherical particles containing some or no detectable vesicular surface components were produced. The apoCs to apoE ratios, as determined by densitometric scanning of the SDS polyacrylamide gradient gel, were 2.89 in control VLDL and 2.27, 0.91, and 0.22 in VLDL core remnants produced in the absence and in the presence of low and high HDL levels, respectively. In vitro lipolysis of VLDL markedly increased binding to HepG2 cells at 4 degrees C and internalization and degradation by human hepatocytes in primary culture at 37 degrees C. However, the HDL-mediated decrease in the apoCs to apoE ratio had a minimal effect on binding, internalization, and degradation of VLDL core remnants by HepG2 cells and human hepatocytes in primary culture. In order to determine whether HepG2 bound VLDL and VLDL core remnants are deficient in apoCs, (125)I-labeled VLDL and VLDL core remnants were added to HepG2 culture medium at 4 degrees C. The bound particles were released by heparin, and the levels of (125)I-labeled apoCs and apoE, relative to apoB, in the released particles were examined. When compared with those initially added to culture medium, the VLDL and VLDL core remnants released from HepG2 cells had a markedly increased (113%) level of apoE and a reduced (30-39%), but not absent, level of apoCs. We conclude that apoCs, as a minimum structural and/or functional component of VLDL and VLDL core remnants, may not have an inhibitory effect on the binding of VLDL or VLDL core remnants to hepatic apoE receptors.
Albumins↗
Use of carboxypeptidase Y propeptide as a fusion partner for expression of small polypeptides in Escherichia coli.
The carboxypeptidase Y (CPY) propeptide from Saccharomyces cerevisiae was developed as a fusion partner for the efficient expression of small polypeptides in Escherichia coli. Six consecutive histidine residues (6xHis) were fused to the N-terminus of the CPY propeptide for the facilitated purification of fusion proteins using immobilized metal ion affinity chromatography. In addition, a methionine or the pentapeptide (Asp)(4)-Lys linker was inserted at the junction between the CPY propeptide and the target polypeptide to release the target polypeptide by digestion with cyanogen bromide or enterokinase. Therapeutically valuable peptide hormones, such as salmon calcitonin precursor (sCAL-Gly), a fragment of human parathyroid hormone (hPTH(1-34)), and human glucagon were successfully expressed in E. coli as fusion polypeptides with the fusion partner. SDS-PAGE analyses showed that the majority of the expressed fusion sCAL-Gly and fusion hPTH(1-34) were present in the form of inclusion bodies, whereas about 66% of the expressed human glucagon was in a soluble form. Almost complete cleavage of the fusion polypeptides was obtained by digestion with enterokinase. Reverse-phase HPLC analyses showed that the target polypeptides released from the fusion proteins were identical to their native forms.
Calcitonin↗
Synthesis of sesquiterpene derivatives as potential antitumor agents; elemane derivatives.
Derivatives of elema-1,3-diene were synthesized in several steps as polar analogs of beta-elemene, antitumor agent under clinical phase. The lactone ring of compound 1 was opened by LiAlH4 to give diol 2 which was selectively protected by TBDPSCl. After acetylation of the secondary alcohol, the acetylated product was ozonolyzed and reduced to give elemane derivative 4 which was converted to diolefin 8 via selenides subsequent deprotection by tetrabutylammonium fluoride gave two compounds 9, 10.
Antineoplastic Agents↗
Studies on the synthesis and in vitro antitumor activity of the isoquinolone derivatives.
3-Arylisoquinolin-1(2H)-ones (2) are possible bioisosteres of the 5-[4'-(piperidinomethyl)phenyl]-2,3-dihydroimidazo[2,1-a]iso quinoline (1) which is in clinical evaluation for the treatment of cancer. Structure-activity relationship studies of 3-arylisoquinolin-1(2H)-ones (2) led to the synthesis of 3-arylquinolin-2(1H)-ones (3). A number of 3-phenyl substituted quinolin-2(1H)-ones were synthesized and tested for their in vitro antitumor activity against four different human tumor cell lines and 3-phenyl-N-benzyl-3,4-dihydroquinolin-2(1H)-one (12) showed the most potent activity.
Antineoplastic Agents↗
Novel angiotensin-I-converting enzyme inhibitory peptides derived from recombinant human alpha s1-casein expressed in Escherichia coli.
Recombinant human alpha s1-casein expressed in Escherichia coli was purified and digested with trypsin in an attempt to find peptides with angiotensin-I-converting enzyme (ACE) inhibitory activity. Three novel ACE inhibitory peptides, A-II, B-II and C, were isolated and their amino acid sequences identified as Tyr-Pro-Glu-Arg (residues 8-11), Tyr-Tyr-Pro-Gln-Ile-Met-Gln-Tyr (residues 136-143) and Asn-Asn-Val-Met-Leu-Gln-Trp (residues 164-170) respectively. ACE inhibitory activities were measured for the corresponding synthetic peptides, and the ACE IC50 (the amount of peptide causing 50% inhibition of ACE activity) values of A-II, B-II and C estimated to be 132.5, 24.8 and 41.0 mumol/l respectively. Peptides A-II and C were resistant to further digestion by pepsin, whereas peptide B-II was hydrolysed. All three peptides were resistant to digestion by chymotrypsin. These ACE inhibitory peptides may prove useful for oral administration in the treatment of hypertension.
Amino Acid Sequence↗